Liquid crystal display (LCD) technology is one of the most commonly used display technologies at present, and has dominated a prevailing technical position in the flat panel display field for a certain period. Liquid crystal molecules itself are not luminous, and images or characters displayed thereby are the results of modulating the light sent by the backlight source, and the backlight source is an important component determining the display performance of the liquid crystal display, and the brightness of the backlight source directly determines the display brightness on an LCD surface.
A liquid crystal backlight source system is primarily comprised of a light source, a light guide plate, various kinds of optical diaphragms and structural members. Its development tends towards the diversification of size and light-weighting, and requirement of high brightness. Current types of backlight sources mainly contain electro luminescence (EL), cold cathode fluorescent tube (CCFL), light emitting diode (LED), etc., which are divided into a side-light type and an end backlight type according to different positions thereof. Along with the development of the LCD modules, the side-light type CCFL backlight source of high brightness and thin thickness becomes a main stream. But due to its significant large power consumption, it cannot meet the requirements of energy conservation and a portable information product. Therefore, how to improve the backlight source brightness to further increase the LCD brightness without increasing the power consumption has become one of the main challenges of the development.
The major optical diaphragm of the liquid crystal backlight system comprises a reflective film of which the effect is to reflect light emitted from the light source at high efficiency without losses to a light emitting direction of the backlight source thus to reduce light losses and reach objects of raising brightness of the backlight or decreasing power consumption, a diffusion film and a brightness enhancement film.
How to improve the optical property of the reflective film to increase the reflectivity, making the light emitted by the light source be utilized to the highest degree, thereby reducing loss, is the important problem to be solved now in the art. Moreover, in actual applications, it is also required that the reflective film be stable in the ultraviolet resistant performance upon prolonged use; and when the temperature gradient is higher, the dimension deformation difference of the reflective film is small, and does not affect its assembly and use.